1. Field of the Invention
The present invention is directed to apparatus and method for continuously producing foam material or the like. More particularly, it pertains to a novel and improved method and apparatus especially adapted for use in continuously forming a foam material or the like from a variety of curable synthetic resins and foaming agents expanded by air.
2. Description of the Prior Art
Heretofore, it has been rather common practice in the field of producing plastic foam or the like to employ a foam-gun for the purposes of intermixing the constituents of the foam material and, thereafter, applying the resultant admixture to a particular body surface. Various types of known foam-gun constructions have in general been proposed, and to some extent generally accomplish the basic functions of intermixing and applying such admixture which contains the constituents typically forming the foam material. One such type of prior construction is described in U.S. Pat. No. 3,434,805. As disclosed in the above referenced patent, a curable synthetic resin is introduced into an annular layer of foam-forming material which has already been expanded by air. Such an arrangement, however, while performing the noted basic operations is subject to several shortcomings which detrimentally affect a complete and satisfactory operation thereof under normal working conditions. For instance, with such aforenoted type of construction, there is a relatively high likelihood of clogging developing. Moreover, with this kind of construction, somewhat of a greater difficulty might also be experienced in gaining access to the nozzle should it be desired to clean and change the same. In addition, to achieve a mixture of components such gun construction relies on a relatively thin cone-shaped layered stream of resinous material. A thin layered stream, however, does not achieve as great a homogeneous admixture of constituent materials as could be desired and, therefore, is not entirely successful.
Other conventional types of prior art foam-gun constructions, such as described in U.S. Pat. Nos. 2,860,856 and 2,941,900, serve to introduce the resinous and other appropriate materials at angles relative to an axial line extending through the foam-gun. It has been found that whenever a material, such as, for example, resin, is introduced at an angle to the path of other materials flowing through the foam-gun which travel in a general axial direction in the gun, there is a likelihood of a slight restriction occurring at the discharge end of the gun and the materials have a tendency to back up. This restriction results by reason of the fact that the resinous material will not only act to impede or slow the normal flow rate of the material already traveling in the foam-gun but also has more or less of a tendency to solidify whenever it comes into contact with the other materials. As a consequence thereof, and as noted earlier, the materials tend to solidify and clog up the major portion of the gun. Normally the clogging occurs at the barrel where the pressure is. Hence, such kinds of foam-guns have a relatively great tendency to not satisfactorily perform their intended operations. Accordingly, such clogging necessitates an increased amount of maintenance and repair which, in turn, results in loss of production time and an increase in maintenance costs. Moreover, the foregoing category of foam-gun is relatively more difficult to clean by virtue of its construction.
As previously indicated, heretofore known types of foam-guns utilize a rather standard type nozzle for purposes of providing an atomized spray. Ordinarily, in this particular field, there are different types of nozzles which produce different spray effects. One such standard type has a head portion with a plurality of relatively narrow slots which run in a generally zig-zag fashion. These slots converge toward the forwardmost section of the head portion and serve to enable the formation of an atomized spray. Such spray normally takes the configuration of a hollow cone wherein the particulate forming the spray is somewhat heavily concentrated in a rather thin outer layer. Accordingly, the center of this cone is virtually void of spray particulate. A shortcoming associated with this form of hollow cone spray is, of course, that it does not present a solid atomizing effect, that is to say, the particles thereof are not generally uniformly distributed throughout the cone. Consequently, of course, any resulting mixture of such particles with other materials is not as intimately and homogeneously admixed. As a result, heretofore known nozzle insert constructions fail to provide an arrangement which will enable the formation of a solid atomizing spray effect, much less one which can perform such, in a manner which is simple and relatively inexpensive to achieve.
Another disadvantage normally associated with known kinds of foam-guns is the relatively complicated and expensive maintenance which occurs whenever conventional froth inducing devices in foam-guns are cleaned. One form of conventional froth inducing device consists of a plurality of small bead-like members having about a 2 mil diameter and numbering approximately 500 in a typical foam-gun chamber. To satisfactorily clean such bead-like members requires the expenditure of considerable effort in order to remove chemicals which have accumulated on the surface thereof, as well as, in certain circumstances, separating beads which have become joined together. As is believed evident from the foregoing, the maintenance of such froth inducing devices is somewhat time consuming and expensive.
As can be readily appreciated from the foregoing general description of known kinds of foam-guns and nozzles therefor, such are subject to several operational disadvantages in the field.